Hall C - 12 GeV pCDR

Max. Central Momentum 11 GeV/c 9 GeV/c Min. Scattering Angle 5.5 deg 10 degMomentum Resolution .15% -.2%Solid Angle 2.1 msr 4.4 msrMomentum Acceptance 40%Target Length Acceptance 50 cmOpening Angle with HMS 16 deg 25 degConfiguration QQ(DQ)Bend Angle 18.4 deg

Hall C at 12 GeV:HMS + SHMS

• Charged particle detection with momentum up to beam energy z = Eh/ = 1

• Small angle capability essential to measure charged particle along momentum transfer h // q ± few o

• Precision L/T separations

• General Infrastructure for Dedicated Experiments

Exclusive and Semi-Exclusive Reactions (z > 0.3) at high Q2

Separation of Polarized and Unpolarized Structure Functions over large range of x and Q2

Lcos(2)TT[()/2]1/2cos(LT

Hall C at 12 GeV: SHMS Carriage and Shield House

16° SHMS-HMS angle.

Hard connections to pivot yield 0.01° scattering angle, 0.5mm pointing reproducibility.

1m shielding typ.

SOS

Hall C at 12 GeV: Co-Existence of SHMS with HMS

HMS: QQQD SHMS: QQ(QD)

Hall C at 12 GeV:HMS

Option: replace Cherenkov with FPP

Hall C at 12 GeV: HMS Performance

Parameter HMS Performance Range of Central Momentum 0.4 to 7.3 GeV/c Momentum Acceptance ±10% Momentum Resolution 0.1% - 0.15% Scattering Angle Range 10.5 to 90 degrees Maximum Target Length at 90 degrees 10 cm Horizontal Angle Acceptance ±32 mrad Vertical Angle Acceptance ±85 mrad Solid Angle Acceptance 8.1 msr Horizontal Angle Resolution 0.8 mrad Vertical Angle Resolution 1.0 mrad Vertex Reconstruction Resolution (Ytar)

0.3 cm Maximum Flux within Acceptance ~5 MHz Electron-hadron discrimination 1000:1 at 98% efficiency Pion-kaon discrimination 100:1 at 95% efficiency

Hall C at 12 GeV: HMS Performance

Hall C at 12 GeV: SHMS Quads - Based on Existing HMS-Q1

• Slightly increased gradient (8.6 T/m) compared to HMS-Q1• TOSCA (JLab) and external feasibility study show there are no issues• Design and Tooling still available at company affordable

Hall C at 12 GeV: SHMS Combined Function Magnet

• Quadrupole “inside” Dipole to reduce current density • TOSCA (JLab) and external feasibility study

• cryostability• coil, conductor conservative• force containment will require careful engineering, but no excessive forces• energy quench within allowable margins

• “Can be built without prototyping or R&D”

Hall C at 12 GeV: SHMS Specifications

Parameter SHMS Specifications Range of Central Momentum 2 to 11 GeV/c Momentum Acceptance -15% to +25% Momentum Resolution < 0.2% Scattering Angle Range 5.5 to 25 degrees Maximum Target Length at 90 degrees 50 cm Horizontal Angle Acceptance ±18 mrad Vertical Angle Acceptance ±50 mrad Solid Angle Acceptance 4 msr (LSA tune)

2 msr (SSA tune) Horizontal Angle Resolution (yptar) 2-4 mrad Vertical Angle Resolution (xptar) 1-2 mrad Target Resolution (ytar) 0.2 - 0.6 cm Maximum Flux within Acceptance ~5 MHz Minimum Acceptable e/h discrimination 1000:1 at 98% efficiency Minimum Acceptable /K discrimination 100:1 at 95% efficiency

Hall C at 12 GeV: SHMS Small-Solid-Angle Tune Model

∂=+10%

∂=-10%

≥5.5° ≤ 11 GeV/c

2.32 mTo LSATune.

Eff. Sol. Angle ~ 2 msr

Hall C at 12 GeV: SHMS Large-Solid-Angle Tune Model

∂=+10%

∂=-10%

≥10° ≤ 8.8 GeV/c

2.32 mTo LSATune. Eff. Sol. Angle ~ 4 msr

Hall C at 12 GeV: SHMS Acceptance

Point Target

LSA TuneSSA Tune

Hall C at 12 GeV: SHMS Acceptance

50cm Target(viewed at 90o)

LSA TuneSSA Tune

Hall C at 12 GeV: DetectorsSmall Solid Angle Tune Resolutions

Hall C at 12 GeV: Detectors:Detector Package in the Shield House

Hall C at 12 GeV: DetectorsSHMS Detector Requirements

Characteristic Requirement Tracking Resolution (each of two points) 100 µm DC < ~ 1% X0 Multiple Scattering Nothing upstream of DC

at low momentum.

Minimum material upstream of Cerenkovs

Size From 85x110 cm2 at DC To 115x150 cm2 at LGC

Particle Identification Combination of Techniques to cover this wide momentum range.

Argon/Neon Cerenkov

HGCS1XS1Y

AGCDC1 DC2

TRD S2X S2Y LGCA1

C4F10 Cerenkov

Elevation

Argon/Neon Cerenkov

HGCS1X S1Y

AGC

DC1 DC2

TRD S2X S2Y LGCA1

C4F10 Cerenkov

Plan

Hall C at 12 GeV: Detectors:Size Summary

SHMS Detector Active Areas (cm)

• Will design detectors assuming 50-cm target• Will instrument assuming 30-cm target (both as viewed at 90o)

Hall C at 12 GeV: DetectorsWire Chambers - Stack-up Design

Hall C at 12 GeV: DetectorsWire Chambers - SOS Resolution

Hall C at 12 GeV: Detectors:Particle Identification

SHMS will use a COMBINATION of PID techniques to cover the entire momentum range of interest.

Electron/Hadron Separation:

•Time-of-Flight at low momentum.

•Shower counter over full range.

•e- always trigger Cerenkov counters.

•Additional upstream Cerenkov at high energy

Hall C at 12 GeV: Detectors:Particle Identification

1 to 3 GeV/c Pion/Kaon Aerogel CerenkovKaon/Proton TOF & Aerogel

3 to 5.5 GeV/c Pion/Kaon C4F10 CerenkovKaon/Proton Aerogel

5.5 to 11 GeV/c Pion/Kaon Atm. Press. Cerenkov,C4F10 Cerenkov anddE/dx

Kaon/Proton C4F10 at > 1 atm.

Hall C at 12 GeV: Detectors:Atmospheric Pressure Cerenkov

2.5 m longNe (n-1= 67 x 10 -6) and/orAr (n-1 = 283 x 10-6)

Neon

Argon

• Atmospheric pressure - thin windows.

• Use only above 6 GeV (e.g., e/ separation for x > 1 experiment)

• Improves e/π (argon) or π/K (neon).

• Expect ~10 p.e.

Hall C at 12 GeV: Detectors:Particle Identification Summary

Hall C at 12 GeV: Detectors:Focal Plane Polarimeter

The FPP being built for the HMS can also fit in the SHMS.

Argon/Neon Cerenkov

AGC

DC1 DC2 LGC

FPP FPP

S1XS1Y S2X S2Y LGC

Pion Form Factor

Essential:• 9 GeV/c (at Q2 = 6 GeV2)• 5.5 degrees (with HMS at 10.5 degrees!) • precise L/T (smooth acceptances)

(Semi-)Exclusive Meson Production

• Can access deep exclusive charged /K electroproduction to Q2 ~ 10• Large range in z (0.3-0.8), x (0.2-0.7), Q2 (3-10 GeV2), and pT in semi-exclusive meson electroproduction for duality and factorization studies and, if applicable, spin/flavor parton distributions

Proton-Delta Transition

|Can access magnetic transitionform factor up to Q2 = 18 GeV2

(typ. Q2 ~ 15 GeV2)

Assumption: E2/M1 remainssmall. If not higher Q2 maybe possible

Crossing Charm Threshold

|

Small Cross Sections requirehigh luminosity hall

Requires detection of two chargedparticles with ~6.5 GeV/c momentum

p op also possible using BigCal (under construction)

Separated Structure Functions x = 0.8

+ R F1 and F2 (F1 and FL) + A// + A_ g1 and g2

+ x > 1 in Nucleus|

H,D(e,e’)

Structure Function Moments Lattice QCD• F2

• p – n• Q2 = 4 GeV2

(x@W2=4 = 0.56)

• n = 2, 4

Experiment• “F2”• 2p – d (or CTEQ/MRST/GRVS)

• Lack of large x (resonances and elastic!)

Mn(Q2) =0 1 dx xn-2F2(x,Q2)

+ Structure Functions + Duality Studies + Q2 Evolution Studies

DIS-Parity

Requirements:• spectrometers at 12.5 degrees (HMS + SHMS = 12 msr)

• ~2 kW cryogenic cooling (QWeak wants 2.2 kW, ~ 90 A and 60 cm LD2) • 1% Polarimetry (Qweak wants 1.4%)

Utilizes Hall Cinfrastructure

Color Transparency

|

A(e,e’p) requires Q2 > 12 GeV2 A(e,e’) can reach Q2 = 14 GeV2 at larger t

AGSA(p,2p)

Hall C at 12 GeV:HMS + SHMS

• Charged particle detection with momentum up to beam energy z = Eh/ = 1

• Small angle capability essential to measure charged particle along momentum transfer h // q ± few o

• Precision L/T separations

• General Infrastructure for Dedicated Experiments

Exclusive and Semi-Exclusive Reactions (z > 0.3) at high Q2

Separation of Polarized and Unpolarized Structure Functions over large range of x and Q2

Lcos(2)TT[()/2]1/2cos(LT